Properties of methicillin-resistant Staphylococcus aureus colonizing patients in a burns unit

One hundred cultures of methicillin-resistant Staphylococcus aureus (MRSA) were isolated from patients in a Regional Burns Unit between December 1984 and May 1985. These organisms produced large amounts of beta-lactamase which readily hydrolyzed flucloxacillin but they were sensitive to teicoplanin, dicloxacillin and cephalothin at 37.5 degrees C. The MRSA strains did not differ from methicillin-sensitive isolates in sensitivity to unsaturated fatty acids, survival in serum and plasma or desiccation. However, each culture of this strain was negative or only weakly-positive for bound coagulase and cell bound protein A. Few (eight out of 44) cultures contained plasmids and the resistance to four antibacterials was not transferable in mixed cultures. No attempt was made to isolate patients colonized with MRSA which were rarely isolated elsewhere in the hospital.